Might be some small things that won't work, but in general you should be 
fine.

Of course, as time goes on, those small things will get bigger and bigger. 
Still, basic HTML with basic javascript should be fine for a long time. It 
all depends on what kind of content you want.

May I ask why you're running such an old version of Ubuntu?

On Fri, 21 Feb 2014, paul g wrote:

> For a basic home/office computer user running an older FireFox version say
> '20.0' under Ubuntu 10.04 etc '2.6.-- kernel' will new web pages and webpage
> design soon require the need for a later version of FireFox or Opera to
> 'surf' the web? Just a curious question I am a noob.
> 
> Thank You.
> 
>